LED replacement products for fluorescent lamps, in particular in tubular form, for example “T5” or “T8” with lengths of 59, 120 or 150 cm, are known under the designation retrofit lamps. Criteria for retrofit lamps with a base at two ends as a replacement for fluorescent lamps are set down in the standard IEC 62776. In particular, in this case very stringent requirements are placed on the test voltage from one side of the lamp to the other side of the lamp, to be precise 4*U+2000 V, where U is the operating voltage, which gives 2960 V on an operating voltage of 240 V. Thus, in the case of a retrofit lamp which is inserted into a luminaire on one side, even when a voltage of approximately 3000 V AC is applied, there should be no flashover to the uninserted side of the retrofit lamp. In order to be able to adhere to this specification, it has become commonplace in the case of known retrofit lamps for said retrofit lamps to have their electrical connection on only one side, while the other side merely loops through the electrical current, precisely as in the case of the starter which is replaced by a replacement starter which represents a short circuit electrically.
Care is therefore taken in the interior design of the retrofit lamp to ensure that sufficient leakage paths and air gaps are maintained between the printed circuit board bearing the LEDs and the electronics for operating the LEDs, which are coupled to the first connection, on one side, and to the second connection on the other side, in order to be able to maintain the abovementioned dielectric strength of at least 3000 V AC test voltage.
In the past, during operation of such known retrofit lamps on different ballasts, sometimes damage, and even failure of the ballasts have been observed.